The invention relates to a method and a jig for dyeing textile webs made of polyester fibers (PES fibers) or blends of PES fibers with other natural fibers, particularly cellulosed fibers such as cotton, but also, inter alia, linen and wool, as well as synthetic fibers such as viscose fibers, among other. In the method, a continuous material is unwound from a fabric batch, conducted through a dye bath, and subsequently reeled again to form a fabric batch. This process is repeated in each case by reversing the direction of the web movement.
The receptivity of polyester fibers to dyes is considerably poorer compared to other customary textile fibers. This is due to their closed structure, and their high degree of orientation. This results in low swelling capacity and hydrophobic properties. In addition, the polyester fiber contains no free dye sites and has only a slight affinity for water-soluble dyes.
With but a few exceptions, only disperse dyes are usable for polyester fibers, and then the polyester textiles are dyed according to the following three basic methods:
1) Dyeing at temperatures up to 100.degree. C. on dyeing machines operating at atmospheric pressure, using special aids--the so-called "Carrier"; PA1 2) Dyeing at temperatures between 120.degree. C. and 130.degree. C. on "HT" (high-temperature) dyeing machines operating at elevated pressure; PA1 3) Thermosol dyeing method in which the dye applied on the material is set by dry heat in the temperature range of 190.degree. C. to 220.degree. C. PA1 a) Dye utilization when dyeing under atmospheric pressure at least 65% or more, given 2% dye, i.e. given 2% of the fabric weight in dyestuff in the liquor. PA1 b) Light fastness, given equal depth of color, at least 5 (German Industrial Standard DIN 54004). PA1 c) Laundering fastness at 60.degree. C., at least 4/4-5/4-5 (DIN 54010). PA1 d) Fastness in the reductive medium. PA1 Color Index Disperse Yellow 3 such as Cellitongelb G (BASF) PA1 Color Index Disperse Yellow 60 such as Resolingelb RL (Bayer) PA1 Color Index Disperse Yellow 68 such as Samarongoldgelb HGL (Hoechst) PA1 Color Index Disperse Orange 3 such as Cellitonorange GR (BASF) PA1 Color Index Disperse Red 1 such as Cibacetscharlach 2B (Ciba-Geigy) PA1 Color Index Disperse Red 50 such as Resolinscharlach RR (Bayer) PA1 Color Index Disperse Violet 1 such as Cibacetviolett 2R (Ciba-Geigy) PA1 Color Index Disperse Blue 81 such as Resolinblau GRL (Bayer)
Because of the comparatively low liquor pickup of approximately 35%, the thermosol method is disadvantageous for the dyeing of textile webs made 100% of polyester fibers. The evenness of the dye take-up leaves something to be desired, in particular. Moreover, like all continuous methods, the thermosol method is only economically suitable for larger dye lots.
Dyeing with the aid of carriers (the first approach listed above) was frequently utilized primarily during the first phase of the introduction of polyester fibers into textile production. Today, however, its use has fallen off sharply. The carriers already permit sufficient swelling of the PES fibers at temperatures of 95.degree. C., and thus promote the diffusion of the dye into the PES fibers. However, the carriers are usually toxic, and their use is not in harmony with protection of the environment.
Therefore, predominantly high-temperature dyeing from 120.degree. C. to 130.degree. C. is used as an exhaust-dyeing process. However, it is only possible to dye at temperatures over 100.degree. C. on equipment which is constructed for an excess pressure corresponding to the temperature range indicated.
Thus, it is known to use a "HT jig" for dyeing PES fibers with disperse dyestuff, said HT jig permitting a dyeing temperature in the range from 120.degree. C. to 130.degree. C. For this purpose, the jig housing must withstand a steam pressure between approximately 2 and 5 bar. The construction and operation of such an installation are correspondingly costly.
The French patent FR-A-1333808 discloses a jig for, among other things, dyeing polyester, in which, before the web is reeled onto one of the lap rolls, steam is sprayed onto the fabric web from both sides, the intention being for the steam to pass over the surface of the fabric. After applying the steam, and before winding onto the lap roll, the fabric web passes a guide roll/fabric spreader combination. However, this specific design is less than optimal, and can be improved upon.